RIO DE JANEIRO -- Former No. 1 Rafael Nadal said Monday he's not frightened by the Zika virus as he prepares in Brazil -- the centre of the viral outbreak -- for this week's Rio Open tennis tournament and the city's Olympics in less than six months.

Nadal won Olympic gold in the Beijing Olympics, but missed London with an injury.

"I'm doing the things the people have told me," Nadal said. "I'm going out at night. I'm not scared. I'm not worried about this. If it happens, it's bad luck."

Nadal is the top-seeded man in the tournament and fellow Spaniard David Ferrer is No. 2. Both said they were confident the tournament was doing all it could to control the mosquitoes that spread the virus.

The virus is being linked to birth defects, and pregnant women have been cautioned not to travel to the country.

"I don't know how serious the situation is," Nadal said. "I see people living here totally normally. I see people on the streets, on the beach and in the restaurants. Things are going on like normal."

Brazil began a week-long campaign of spraying pesticides and distributing informational leaflets with more than 200,000 soldiers spread out across the country.

Brazilian President Dilma Rousseff has said "we're at war against the mosquito" and she has repeatedly guaranteed the outbreak will not derail the Olympics that open Aug. 5.

Ferrer said he'll wear long sleeves and long trousers when he goes out socially in the morning and evening.

"I'll try to take those precautions, but I'm not obsessed about it," Ferrer said.

Both Spaniards were asked to reply to comments last week by Spanish swimmer Mireia Belmonte, a two-time Olympic silver medallist in London in 2012, who said she "would not attend" the Olympics if she thinks her health is at risk.

She echoed American women's national soccer goalkeeper Hope Solo who said last week "if the Olympics were today, I would not go."

Neither Nadal nor Ferrer elaborated on Belmonte's comments.

"I have talked to the local players here, and they are not giving it much importance," Ferrer said. "There is a lot still to be known about Zika and nothing is 100 per cent certain."